BioEd Online

A leading Himalayan seismologist is struggling to gain entry into Pakistan to make critical measurements of the after-effects of the earthquake that struck on 14 October.

Roger Bilham of the University of Colorado at Boulder says that the Pakistani embassy in New Delhi, India, has so far denied him the visa he needs to visit his field sites and make measurements that could give an indication of future quakes in the region. "I'm disappointed but not angry," Bilham said from a room at the New Delhi YMCA. "They have just suffered this awful, awful disaster and they have a lot to handle."

Bilham is still trying to get access to the country, and says he is cautiously optimistic that a visa could be granted as early as tomorrow. But he adds that if he is denied entry much longer, valuable geological information about the quake could be lost. "It is a very rare occurrence to have an earthquake of this size in this region," he says. "It is like a Rosetta Stone that will allow us to view the history of the Himalayas."

The earthquake that struck the Pakistani-administered region of Kashmir had a magnitude of 7.6. It resulted in tens of thousands of fatalities and the destruction of entire villages in the remote mountain region. After the disaster, Bilham left his work in the Andaman Islands, the site of the quake that caused the December 2004 tsunami in the Indian Ocean, and rushed to northern India in an attempt to do field work at the site.

Slipping fast and slow

The quake was caused by a build-up of stress where India collides with Asia. Bilham says that he and his colleagues had predicted a few years earlier that stress in this particular region would result in a catastrophic slip of tectonic plates¹.

Bilham would now like to measure any 'slow slip' that may now be occurring in the aftermath of the quake. In the days and weeks following an earthquake, he explains, the ground along the fault can continue to subtly move, releasing tension as it does so.

Measuring how much it moves is important because it tells researchers about the likelihood of another major quake in the region. If the faults in the region bleed off much of their tension through slow slip, it would mean that the chance of another catastrophic earthquake is far less, at least in the near future.

Bilham is uniquely able to measure slow slip because he has placed a series of pins at key points in the region. Using a global positioning system (GPS), Bilham and collaborators at Pakistan's National Centre of Excellence in Geology in Peshawar had previously measured the location of the pins, long before the recent earthquake. If they can now make a series of measurements following the quake, they will have a better idea of how much tension is being released by slow slip. "This is something that may be happening but we'll never know unless we measure it," he says.

Access rights

Unfortunately, Bilham says, he has so far been unable to contact his colleagues in Peshawar about follow-up measurements. Furthermore, he says that he is the only GPS specialist in the group, and therefore needs to return to the region to train the Pakistani researchers. If he cannot gain access soon, he worries the data may well be lost forever.

It's a worry shared by Philip England, a geologist at Oxford University in the United Kingdom. Only about a dozen measurements of slow slip have ever been made worldwide, he says, and Bilham's work would be a welcome addition. Furthermore, England says it will probably be the only measurement from the region because little geology is done in the politically volatile area. "As far as I know, Roger's the only one mad enough to do it," he says.